The global economy needs to put more money into investments that help growth, and less into speculative financial products that could go sour in a downturn.

That is one message from a study by the International Monetary Fund, presented Wednesday in Washington at the annual meeting of the IMF and the World Bank.

IMF financial counselor Jose Vinals says a long period of low interest rates has prompted some investors to seek higher returns in riskier ventures. Those investments might collapse and threaten the stability of the financial system if the economic climate turns bad due to the conflict in Ukraine getting worse, or if the U.S. central bank mismanages rising interest rates.

Vinals also says the 300 major banks IMF experts examined are healthier than in the past, but many are still not strong enough to make the loans needed for projects that will boost economic growth.

Problems in the tightly-regulated banking sector mean investors are seeking loans from other types of lenders, which might increase risks to financial stability.

Vinals says policy makers should help banks restructure themselves and do more to supervise non-bank financial institutions.